LED lamps are known. For example, inspection lamps that cause fluorescence of fluorescent materials are widely used for detection of fluorescent materials. For example, fluids that are under pressure can include fluorescent dyes; so that, leaks of such fluids can be detected by illuminating the leaking fluids with such inspection lamps.
One common application of inspection lamps is detection of leaks of the refrigerant in automotive air conditioning systems. Fluorescent dyes that are mixed with the lubricant that is present in automotive air conditioning systems typically visibly fluoresce when illuminated with blue, violet or near-ultraviolet wavelengths. Inspection lamps that would be used for detecting leaks of such fluids would produce blue, violet or near-ultraviolet wavelengths.
In the past, such inspection lamps used incandescent, halogen, or mercury vapor light sources. Now that LEDs that produce the useful wavelengths are available, inspection lamps can be made that are smaller and lighter, have less power consumption, and produce less heat than inspection lamps without LEDs. Furthermore, inspection lamps with incandescent, halogen or mercury vapor light sources required filters to remove undesired visible wavelengths that interfere with seeing the fluorescence of visible materials, while LEDs often produce little enough of undesired wavelengths to not require filters.
It has been found that wavelengths in or near the range of 395-415 nanometers are useful for searching for small quantities of visibly fluorescent materials since wavelengths of 395-415 nanometers are slightly visible. If the light from an inspection lamp is slightly visible, this helps in seeing what is being irradiated with the inspection lamp. Wavelengths longer than 415 nanometers are more visible than shorter wavelengths and typically require the user of the inspection lamp to wear glasses that attenuate or block the visible wavelengths that are produced by the inspection lamp.
Alternatively, inspection lamps that produce wavelengths near 450 nanometers have been found to be useful for some purposes. For example, fluorescent dyes that are added to some oils and automotive fluids do not respond as well to violet and some near-ultraviolet wavelengths as they do to blue wavelengths. As another example, some body fluids weakly fluoresce from both ultraviolet and visible wavelengths, while many fabrics fluoresce from ultraviolet and violet wavelengths but not blue wavelengths longer than approx. 420 nanometers. As a result, police officers searching for body fluids would use blue inspection lamps that cause fluorescence of said body fluids but not of fluorescent fabrics. Typically, inspection lamps that produce blue wavelengths such as 450 nanometers would be used with glasses that block the visible wavelengths produced by such inspection lamps.
While LED lamps, such as LED inspection lamps, already exist, they can be improved upon.